Forever SC-16WB ceramic knife

[kwakster]

Question from a member on another knife forum:

"After all this testing would you say benefits of ceramic outweigh the attention required, compared to steel ?"

My answer:

"At this moment i wouldn't say that, as i think ceramic knives in general haven't developed as far as steel knives yet.
Most of them are still too brittle and cannot be resharpened by the end user as easily as most steel types.

This particular knife however has proven itself to me already as an advancement over many other ceramic knives, as the ceramic material certainly has a much higher grindability (fact) and also seemingly a higher toughness (assumption).
While that toughness still isn't in the realm of most steel types i do notice a difference in use by much less edge chipping overall, and the chips that i see are also noticeably smaller (i need my Victorinox loupe to spot them).

What is however even more important in my view is that the ceramic material in this knife has a grindability that is more or less comparable to S90V steel, something i discovered when resharpening the edge on my Tormek T7, which is fitted with a silicon carbide stone.
In only a few slow passes i had a completely new edge.
(as a comparison: S90V steel sharpens like annealed 420J2 when compared to a Kyocera ceramic knife on the same stone)

Now from experience with other ceramic knives i've learned that the resulting edge needs refinement before being used (toothy edges are a no no on most ceramic knives), so that is what i did with the edge on this knife as well (with various diamond compounds), but in a later stage i plan to experiment with less refined edge types a bit to see how these hold up.

All in all more testing is needed to get a better understanding of how the current generation of ceramics in knives perform to have some benchmarks, as i think we will see much more improved types of ceramic in knives (and other articles) in the near future."

[sLaughterMed]

Very cool thread mate! I love the idea of a ceramic knife in my kitchen, but sadly my kids and wife make anything that isn't easily sharpened it cleaned unfeasible for now.

I cant wait until I've properly trained... Er.  Taught them properly

[kwakster]

The knife is still being used in our kitchen in exactly the same way as described earlier, but the edge has now lost it's ability to whittle one of my chest hairs towards the root.
I tried it multiple times on 3 different hairs, but the edge did not catch any of them even once.

The edge can however still shave the hair on both the back of my hand as well as on my leg on skinlevel, but i have to press the edge on my skin a bit or it will slide over the hairs without cutting them.
If i do that it will shave a patch clean.
It will also slice a piece of copy paper to confetti easily, so most non-knife people would still consider the edge to be very sharp.

Through my Victorinox loupe i can now spot 5 micro-chips, which can be felt on my nail as well.
However these are not visible with my naked eyes.

Will continue to use the knife to see how things develop and report back again later.

[zoidberg]

Thanks for the update kwakster.   

[David]

1+

[Etherealicer]

Thanks for the Update.
Nice... or

Compared to other knifes, is that good, average or bad (I'm not asking for myself but for all the noobs too afraid to do it themselves)

[kwakster]

The edge can now no longer cleanly cut the skin of most tomatoes, and on some types even downright sawing motions don't work anymore.
On onions i can feel that initial resistance cutting through the top layers, but on most other foods the knife continues to work well.
It also still scrape-shaves armhair and slices copy paper just fine, so most non-knife people would still call it quite sharp.

Although focussing with my new USB-microscope is still quite the challenge i did manage to take some shots of the current edge from tip to heel, to show the edge damage in the form of microchips as well as the sharpening scratches in the bevels.
My Victorinox magnifying glass had already showed me the larger microchips, but the smaller ones and the scratches which can now be seen clearly had always remained invisible to me.
It looks like i have jumped the other diamond wheels a bit to soon before finishing with the 1 micron diamond wheel, so apparently there is some room for improvement.

[kwakster]

Currently busy removing the microchips from the apex with a Paper Wheel coated with 15 micron diamond compound.
The idea is to finish the new apex with only this compound and then find out how the knife will do with the resulting rather coarse edge (for a ceramic knife)

Although it remains quite difficult to capture the scratch pattern in pictures, the USB-microscope proves to be very useful in showing a sharpening fault (picture 1) and an extremely small chip remnant (picture 2).
Picture 5 also shows that the apex is already becoming translucent with this finish at 25 degrees inclusive.

[sLaughterMed]

Great prictures. I love seeing updates in this thread. Keep up the good work

[toolguy]

Kwakster you are an extremist.LOL.

We can all learn something from your pursuit of the perfect edge.

[Etherealicer]

Kwakster you are an extremist.LOL.

We can all learn something from your pursuit of the perfect edge.

+1

I don't have anything to add really, just wanted to be included in this thread and say thank you

[kwakster]

Before i completely finished the edge to 15 micron i decided to use it just once, cutting up a box of mushrooms, some bell peppers, and some onions on my end grain wooden cutting board.
The 3 pics below show the result: not only microchips, but larger sections of the apex measuring several millimeters have completely broken off.
I think it's safe to say that a 15 micron edge finish is a bit too coarse for this ceramic material.

[kwakster]

First resharpened the old edge with a Paper Wheel coated with 15 micron diamond compound to get rid of the damaged sections in the apex, then refined it just one step with a second Paper Wheel coated with 6 micron diamond compound.
The new apex can whittle a chest hair towards the hair root (this is noticeably easier than towards the point of the hair), and it also has a little more bite.
Will see how this edge finish holds up in our kitchen, as the knife is already in use again:

[Dean51]

You stated earlier you I thinned the edge just a hair to an almost exact 25 degrees inclusive. do you think it would help prevent chipping to go with a 40 degree inclusive egde?
Or do you think the ceramic would still chip at 40 degrees inclusive.

[kwakster]

It might, but then the knife would cut noticeably worse (much more resistance will be felt by the user)
I want the edge angle to be as thin as possible, but thick enough.

[Dean51]

It might, but then the knife would cut noticeably worse (much more resistance will be felt by the user)
I want the edge angle to be as thin as possible, but thick enough.

I was going to modify my post and say perhaps 40 degree a micro bevel.

[kwakster]

That would indeed be an option for later, but at this moment i hope to find out if the thicker 6 micron finished apex will hold up better/longer compared to the thinner 1 micron finished apex (which already did quite well in my view)

A possible problem could be that although that might be the case by itself, there is also the less refined scratch pattern to reckon with in a superhard but brittle material where scratches tend to work as stress risers which could potentially lead to faster chipping.
This approach is thus a bit of a double edge sword, but in the end i hope to find something of a sweet spot (if there is any).

[Dean51]